public class DiskPlatter
{
    public int [][] surface;
    public DiskPlatter(int track, int sector)
    {
        surface = new int[track][sector];
    }

    public void addRequest(Request r)
    {
        surface[r.track][r.sector] = 1;
    }
    
    public void removeRequest(Request r)
    {
        surface[r.track][r.sector] = 0;
    }
}